Ultraviolet lamp systems, such as those used in the heating or curing of adhesives, sealants, inks or other coatings for example, are designed for coupling microwave energy to an electrodeless lamp, such as an ultraviolet (UV) plasma lamp bulb mounted within a microwave chamber of the lamp system. In ultraviolet lamp heating and curing applications, one or more magnetrons are typically provided in the lamp system to couple microwave radiation to the plasma lamp bulb within the microwave chamber. The magnetrons are coupled to the microwave chamber through waveguides that include output ports connected to an upper end of the chamber. When the plasma lamp bulb is sufficiently excited by the microwave energy, it emits ultraviolet radiation in one direction through an open lamp face of the lamp system to irradiate a substrate which is located generally near the open lamp face.
A source of pressurized air is fluidly connected to a housing of the lamp system which contains the magnetrons, the microwave chamber and the plasma lamp bulb. The source of pressurized air is operable to direct cooling air, such as 350 CFM of cooling air for example, through the housing and into the microwave chamber to properly cool the magnetrons and the plasma lamp bulb during irradiation of the substrate by the lamp system.
In some UV heating and curing applications, the lamp system includes a mesh screen mounted at the open lamp face which is transmissive to ultraviolet radiation but is opaque to microwaves. The configuration of the mesh screen also permits the significant air flow of cooling air to pass therethrough and toward the substrate.
In some applications, however, the substrate may require a clean environment, such as in a curing chamber, so that the substrate will not be contaminated during the heating and curing process by contaminants carried by the cooling air in contact with the substrate. Moreover, the substrate may also be somewhat delicate and therefore susceptible to damage in harsh environments, such as under the influence of the significant air flow of the cooling air which impinges upon and possibly disturbs the substrate. Oftentimes, the substrate may also be adversely affected by excessive heat which may be generated by the plasma lamp bulb during the irradiation process. Still further, the substrate may configured about the perimeter of a material, thus requiring multiple and different application of UV light to irradiate the substrate around the product.